Soy sauce originated in China sometime between the 3rd and 5th century from a Soy -based fermented sauce. The 19th century Sinologist Samuel Wells Williams wrote that in China, the best soy sauce is “made by boiling beans soft, adding an equal quantity of wheat or barley, and leaving the mass to ferment; a portion of salt and three times as much water are afterwards put in, and the whole compound left for two or three months when the liquid is pressed and strained“
• Soy sauce is made either by fermentation or by hydrolysis. Some commercial sauces have both fermented and chemical sauces.
• Flavor, color, and aroma developments during production are attributed to non-enzymatic Millard Browning.
Variation is usually achieved as the result of different methods and durations of fermentation, different ratios of water, salt, and fermented soy, or through the addition of other ingredients